Authentication for uploading DUs to Glance in Solum

This blueprint deals with authentication for the action of uploading DU to glance in Solum.

Scenario:
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In Solum, user code will be available primarily through two mechanisms - a) users push code to their public github repo and Solum pulls the code, and b) user pushes their code to a 'remote' in Solum.

In both the above situations, we want to perform the following steps with users' code:
1) Create a DU
2) Push the DU to glance on behalf of the user (using user's credentials)

Questions:
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1) How do we get user credentials for the step 2 above?

2) Do we really need to push DU as user -- why can't we just use 'Solum admin user' for this?